Singer, who leads New York-based Elliott Management Corp., provided most of the $1.7 million that the super-PAC American Crossroads raised in May, according to a filing yesterday with the Federal Election Commission in Washington.

American Crossroads, which is aiding the Republican bid to hold the party’s U.S. House majority and gain control of the Senate, has raised more than $11 million for the 2014 elections. Singer gave $250,000 to the super-PAC in March.

With a net worth of more than $1.8 billion, according to the Bloomberg Billionaires Index, Singer is among the biggest political donors in this year’s campaign. Two years ago, he helped found American Unity PAC, a super-PAC that’s urging Republicans to support same-sex marriage.

American Crossroads has mainly targeted Democrats seeking re-election to the Senate, where Republicans need a net gain of six seats for a majority.

The super-PAC also has spent more than $772,000 to help Republican Elise Stefanik, a White House aide to former President George W. Bush, in a June 24 primary in the district of retiring Democratic Representative Bill Owens of New York.

Super-PACs are permitted to accept donations in unlimited amounts so long as their spending isn’t coordinated with the candidates they’re backing. Federal court rulings and regulatory action in 2010 cleared the way for individuals, corporations and labor unions to make unlimited contributions in federal races through outside groups.